Jupiter has a lot of weather.
It has colorful belts and erupting giant storms. It has ammonia-ice clouds. It has liquid water.
Jupiter also has “mushballs.”
A trio of new papers published today in Nature and JGR Planets, using data from NASA’s Juno spacecraft, have revealed the existence at Jupiter of ammonia-rich hail— “mushballs”—that are formed during its violent thunderstorms.
‘Mushballs’ on Jupiter
Jupiter’s vast lightning storms are thought to be connected to regions where water co-exists as ice, liquid and water vapor. Its thunderstorms form deep within the planet’s atmosphere, where it’s freezing, and they’re so powerful that they carry water-ice crystals into the upper atmosphere.
The first article suggests that these water-ice crystals then react with ammonia gas and turn to liquid, becoming ammonia hailstones. These “mushballs” then fall into the atmosphere and evaporate; a mechanism that keep Jupiter’s deep atmosphere—far below its clouds—fed with ammonia and water.
Meanwhile, NASA’s Juno spacecraft has discovered that the levels of ammonia in Jupiter’s atmosphere are hugely variable, and concentrated around its equator.
Cue a new atmospheric mixing model described in the second article, which posits that thunderstorms and the “mushballs” dry out the deep atmosphere of its ammonia.
Do ‘mushballs’ cause Jupiter’s lightning storms?
It’s thought that lightning needs a liquid, but a third article details how Juno’s close flybys has allowed it to see, for the first time, small lightning storms—observed as bright spots on Jupiter’s cloud tops—produced in colder regions of the planet where liquid water can’t exist.
However, these shallow lightning storms are in the zone where liquid ammonia-water can be create; observational evidence for the “mushball mechanism.”
Developed using data from Juno’s microwave radiometer by the Juno team, the study was led by a researcher at the Laboratoire Lagrange (CNRS/Observatoire de la Côte d’Azur/Université Côte d’Azur) with support from the Center National de la Recherche Scientifique (CNES).
How to see Jupiter in the night sky
That means there’s never been a better time to go look at Jupiter with your own eyes; it’s shining in the southeastern night sky night after dark, as seen from the northern hemisphere.
Wishing you clear skies and wide eyes.